Resurrect Skyeye support :

Add a new option, SKYEYE_WORKAROUNDS, which as the name suggests adds
workarounds for things skyeye doesn't simulate. Specifically :
- Use USART0 instead of DBGU as the console, make it not use DMA, and           manually provoke an interrupt when we're done in the transmit function.
- Skyeye maintains an internal counter for clock, but apparently there's
no way to access it, so hack the timecounter code to return a value which
is increased at every clock interrupts. This is gross, but I didn't find a
better way to implement timecounters without hacking Skyeye to get the
counter value.
- Force the write-back of PTEs once we're done writing them, even if they
are supposed to be write-through. I don't know why I have to do that.

1 files changed, 17 insertions, 1 deletions

diff --git a/sys/arm/at91/at91_st.c b/sys/arm/at91/at91_st.c
index 1960e61..10cccc3 100644
--- a/sys/arm/at91/at91_st.c
+++ b/sys/arm/at91/at91_st.c
@@ -72,7 +72,11 @@ static unsigned at91st_get_timecount(struct timecounter *tc);
 static struct timecounter at91st_timecounter = {
 	at91st_get_timecount, /* get_timecount */
 	NULL, /* no poll_pps */
+#ifdef SKYEYE_WORKAROUNDS
+	0xffffffffu, /* counter_mask */
+#else
 	0xfffffu, /* counter_mask */
+#endif
 	32768, /* frequency */
 	"AT91RM9200 timer", /* name */
 	0 /* quality */
@@ -122,10 +126,18 @@ static devclass_t at91st_devclass;
 
 DRIVER_MODULE(at91_st, atmelarm, at91st_driver, at91st_devclass, 0, 0);
 
+#ifdef SKYEYE_WORKAROUNDS
+static unsigned long tot_count = 0;
+#endif
+
 static unsigned
 at91st_get_timecount(struct timecounter *tc)
 {
+#ifdef SKYEYE_WORKAROUNDS
+	return (tot_count);
+#else
 	return (st_crtr());
+#endif
 }
 
 static void
@@ -134,8 +146,12 @@ clock_intr(void *arg)
 	struct trapframe *fp = arg;
 
 	/* The interrupt is shared, so we have to make sure it's for us. */
-	if (RD4(ST_SR) & ST_SR_PITS)
+	if (RD4(ST_SR) & ST_SR_PITS) {
+#ifdef SKYEYE_WORKAROUNDS
+		tot_count += 32768 / hz;
+#endif
 		hardclock(TRAPF_USERMODE(fp), TRAPF_PC(fp));
+	}
 }
 
 void